SIMON: Turkish riot police fired tear gas and water cannons on demonstrators in downtown Istanbul during a second day of protests. The clashes were triggered by the government's plan to build a shopping mall in a downtown park. Turkish Prime Minister Tayyip Erdogan has called for an immediate end to the protest. NPR's Peter Kenyon joins us from Istanbul. Peter, thanks for being with us.

PETER KENYON, BYLINE: Hi, Scott.

SIMON: Can you give us some background on these demonstrations?

KENYON: Well, it's really been kind of remarkable, Scott. This was an environmental sit-in to protect a park in downtown Istanbul, the last green space in the area. It started out quietly a few days ago and then every time the police moved in to sweep out the demonstrators, more joined the next sit-in until yesterday, we had thousands of people confronting the police and they responded with tear gas and high pressure water trucks and wound up making international news.

The numbers are still evolving, but at least dozens have been wounded. Some doctors are putting the number quite a bit higher than that. Some of the more serious wounds are from being hit by the gas canisters. And as I witnessed in Bahrain a couple years ago, that can be fatal if it's from too close a range. So basically, in the space of a few days, this small environmental sit-in has ballooned into multiple large-scale anti-government protests that have now spread to Ankara and Izmir and show no signs of dying down.

SIMON: Well, why? Do you have a clue? I mean, the United States, the EU are criticizing the government's what seems to be the harsh response to the protest. Why such an aggressive response to what seemed to be peaceful protests?

KENYON: Well, there is a history of that here, but in this case, that is precisely what a lot of people are wondering. There really wasn't much indication that this sit-in would have grown like this if they had been left alone for a few days. But this relentless crackdown has essentially tossed fuel onto a smoldering anger against a whole series of actions that the ruling party has made recently; restrictions on alcohol, mob attacks on people seen kissing in public. More aggressive development of green spaces, projects much bigger than this one. Those have Turks on edge and its inflamed disparate groups around the country. And this incident seems to have attracted them all like a magnet.

SIMON: Beyond the question of this immediate park, is there a larger problem for the Turkish government, which is increasingly trying to market Turkey as a world tourist destination, and there's even talk of trying to enter an Olympic bid.

KENYON: Well, yes, I can tell you anecdotally, I've run into a number of tourists here that said this wasn't what they signed up for when they booked their Turkish holiday. I was in the subway yesterday - not by choice - I was swept up in a crowd fleeing underground to get away from the gas. And some of the visitors in that crowed looked as if they were escaping from a disaster area. I had no idea if the scenes that we've seen yesterday and today will affect members of the International Olympic Committee, but commentators here are saying this can't help. Prime Minister Erdogan has made this a key component of his longstanding bid to promote Istanbul as a world city. And so the government, not to mention business leaders poised to vie for huge contracts, should Turkey win the bid, they can't be pleased by these events.

SIMON: You seen any sign of a change of approach today, either on behalf of the demonstrators or the government?

KENYON: So far all I'm seeing is hardening positions. The opposition parties are now joining in calling for even bigger turnouts. Prime Minister Erdogan has said: If you bring out 100,000, I'll bring out a million. I should mention, Scott, there is a court that has issued a ruling in the meantime staying this project in the park that started the whole thing, but at this point, frankly, I think even canceling the project might not affect these protesters.